The actor played shopkeeper Nels Oleson on the NBC series — which ran from 1974 to 1983 — and recurred in “Little House” specials in following years. Prior to his stint on that show, Bull played Doc on the ABC series “Voyage to the Bottom of the Sea.”

Bull was a fixture as a character actor in TV movies and miniseries throughout the 1980s, and most recently appeared on the Starz political drama “Boss.”